Dry eye, ocular surface disease, and deficient tear syndrome each describes signs of clinical damage to the intrapalpebral ocular surface or symptoms of such disruption from a variety of causes. Included among dry eye-related ocular surface disorders is contact lens-related evaporative tear disruption. Contact lens wear can induce dry eye symptoms in patients who have a pre-existing, asymptomatic, marginally dry eye condition. Contact lens materials use greater surface wetting than the corneal epithelium. Wearing contact lenses thins the preocular tear film and interferes with the spreading of mucin onto the cornea. Thus, new contact lens materials are needed that are more hydrophilic.
In other cases, toxic anterior segment syndrome (TASS) is an acute severe intraocular inflammation accompanied by diffuse corneal edema within 1-2 days of anterior segment surgery most commonly associated with cataract surgery. TASS is a form of sterile, noninfectious endophthalmitis with or without pain, marked decrease in vision, diffuse corneal edema that extends limbus to limbus, photophobia, and severe anterior chamber reaction, occasionally with hypopyon. TASS presents within 12-24 hours after surgery where infectious endophthalmitis typically develops 2-7 days after surgery. Thus, new intraocular lens materials are also needed that are less inflammatory, eliminate the need for steroidal treatment, and improve or maintain ocular health.